Abacus



FIG. 1 is a front perspective of the abacus showing my new design;

FIG. 2 is a front view of the abacus shown in FIG. 1;

FIG. 3 is a back view of the abacus shown in FIG. 1;

FIG. 4 is a side view of the abacus shown in FIG. 1, the opposite side view being identical thereto; and,

FIG. 5 is a top plan view of the abacus shown in FIG. 1, the bottom view being flat and unornamented.

The broken line showing the baby bottle indicia on FIGS. 1 and 2 are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for an abacus, as shown and described. 